The within invention concerns a crane with a rotating platform that can rotate on a vertical axle, a boom that is connected to the rotating platform and which can luff on a luffing axle, guying connected on the one hand with the boom and on the other hand with a guy support, which can slew on an axle parallel to the luffing axle of the boom and is connected with the rotating platform and/or the boom foot, as well as an adjustment mechanism, in particular adjustment cabling, that serves for the luffing of the boom and which is connected with the guy support. The invention also concerns a process for raising the boom of such a crane.
The raising of very long booms of cranes, for example crawler cranes, becomes increasingly difficult in proportion to the increase in boom length, since on the one hand the erection moment of the boom lying on the ground becomes very large, and on the other hand the lever arm of the adjustment guying usually connected to the superstructure and the guy support becomes very small in relation to the rotation axle of the guy support or the boom. In order to limit the guying forces or cable forces during erection, theoretically the lever arm of the adjustment guying could be improved by inclining the guy support farther back. However, when the boom was steeply inclined, that is, was rotated at close to 90°, the guy support would then be resting right on the rotating platform.